关系副词和“介词＋which/whom”引导的定语从句 观察思考，观察下列句子，写出黑体词(关系代词)的先行词及在定语从句中所作的成分 ①The time when I first met Nelson Mandela was a very difficult period of my life. (先行词________，时间状语) ②We have reached a stage where we have almost no rights at all. (先行词________，地点状语)